May 1415 min read

Building a Pinewood Derby Big Rig

My name is Mark Robison, as you can see in the image below, I enjoy building Pinewood Derby 18-wheeler big rigs! I make my trucks from scratch without using BSA (Boy Scouts of America) 18-wheeler big rig kits, (which are very hard to find today!) I have provided links at the end of this article where Big Rig kits are available for purchase.

Left side view of a green, white and black Pinewood Derby 18-wheeler big rig on a checker flag background.

A little about myself: I'm involved in our local Cub Scouts. I have a son who is a Webelo 2. I'm a member of the Derby Talk forum under the screen name Whodathunkit. I also help with our local Cub Scouts at the Pinewood Derby every year as their Pinewood Derby chairman. Plus, I'm an avid collector of all things Pinewood Derby. In 2015, I started racing Class A 18-wheelers and Class C big rigs at the Mid-America Pinewood Derby, The West Coast Grand Prix, and the fall Technical Maintenance Council (TMC) big rig race, where the rigs can be made with or without the use of a purchased kit.

From the image below, you can see I've won a few races (though I've also lost a few) using my scratch-built semi-trucks.

Sometimes, I get lucky with the time, effort, and enjoyment I put into making these semi trucks even to take the Best of Show award! With every build, I try to put as much detail as I can into it and make it look realistic by using things like wooden dowel rods, toothpicks, paper clips, telephone cord wire, seed beads, pop cans, and so on as you'll see in the build images to follow. You can find detailed parts for Pinewood Derby cars, but when it comes to semi-trucks, you must find and use plastic model truck parts or get creative and make your parts, which I often do.

Examples of different Pinewood Derby big rig trucks with several trophies won in various big rig races—sketched plans for a big rig and Turbo Derby tools used to construct the trucks.

Usually, I start my Big Rigs by sketching my ideas. I enjoy dabbling in artwork to create the designs for the trucks. I used Turbo Derby products and various woodworking and modeling tools for this build.

Several sketched iterations of the big rig truck design, drafting tools, and Turbo Derby tools used to construct the big rig.

To start the build, I like making the small parts first. I used a mini-wood lathe to turn a 21/64" dowel rod for the air horns and a 3/8" dowel rod for the air filter canisters. Next, I used my pattern to draw the cut lines for shaping the air horns. These were shaped back to back on the lathe and then cut in half in a craft miter box using an X-Acto razor saw. Then, I moved on to shaping the air filter canisters in the same manner.

Design of the truck air horns and air filter canisters. Marking and cutting the features on wooden dowel rods and a small wood lathe with tooling.

The air horns and filter canisters were marked, then turned and sanded on the lathe. Each is done in one piece and then cut in half using a miter box and hobby saw.

Marked dowel rods for the truck filter canisters, features being turned or cut on a lathe, and the completed airhorns and filter canisters.

For the frame, I used 11/16" x 1 3/4" x 8" pinewood from my local lumber yard. I then cut it to 8 1/8" on a miter saw and used my pattern to mark the axle locations.

Pinewood in long pieces, wood cut into smaller pieces on a miter saw, and a wood piece next to the schematic for the truck body.

The axle holes were drilled using a Turbo Jig. The pattern was taped to the frame with packing tape, which acts like a lube to keep the scroll saw blade cool while cutting. For the internal cutouts in the frame, holes were drilled with a drill press.

A wood piece drilled using a Turbo Jig. A truck schematic glued to a wood block with holes drilled in the top on a drill press.

Using a scroll saw with a no. 5 Shark Tooth brand scroll saw blade, I cut out the frame and then moved on to the front and rear fenders by taping the patterns down to the wood blanks. The front fenders were made from 3/8"x 2 1/2" pine, and the rear fenders were made from 7/8" x 4" pine.

Big rig body cut on a scroll saw, the truck fender templates glued to wood blocks and cut on a scroll saw.

I made the cab steps out of scrap pinewood on the scroll saw. I traced them using a small jig made from a past build.

Truck cabin steps traced onto a wood block and cut with a scroll saw.

The fuel tanks are fashioned from a 5/8" dowel rod. These were secured by tank straps cut from scrap pine. To create the straps, I marked and drilled a scrap piece of pine and used a Dremel to sand the hole. The 1/8" straps were then marked on the wood, cut on a scroll saw and shaped to complete the profile.

Fuel tank straps sketched on a wood block. A hole drilled through the wood block. Marks made on the block with pencil, and fuel tank straps cut on a scroll saw.

The fuel tanks were sanded on a belt sander to round over the ends to give them their shape. For the fuel caps on the tanks, I used 1/8" dowel rods.

Fuel tanks shaped on a belt sander, glued to the fuel tank, and placed on a schematic for reference.

The parts for the cab included 1/8" Baltic birch plywood for the doors, back, and floor bottom, pinewood for the firewall, and basswood for the cab top. I cut all of the parts on the scroll saw, and then I chamfer-shaped the cab top with a Dremel tool and sanding drum.

Marks for the truck door and the back and front of the truck cab on Baltic birch plywood using the plans as templates. These items were cut on a scroll saw and then mocked up to show the truck cabin. Items shaped using a Dremel rotary tool.

In the first image below, I was working on sizing the floor bottom and firewall. The second image shows the cut line and shape of the firewall for the cab. The third image shows where I glued the windshield support post, and the last photo shows the initial glue-up of the cab. However, the cab top is still unglued at this point and will be glued on towards the end of the truck build.

The big rig cabin floor, doors, and sides are on a table—block of wood with cut lines marked for the cab firewall. Gorilla glue bottle and windshield support post. The cabin pieces held together with clamps while the glue dries.

In the photos below, I'm gluing the cab down to the frame. In the second photo, I made the front bumper out of 1/8" thick pinewood. The third image shows how the steps, fenders, and balsa hood were glued on. The fourth image gives you a different angle to see how it was done. (On a side note, I used spare wheels and axles while gluing the front and rear fenders.)

Close-up view of the truck fuel tanks and tank straps.

Next, I glued the straps to the fuel tanks. To do this, I marked lines on the tanks to keep the straps evenly spaced and used wood glue with a toothpick to smear glue to the inside. In the second image, you'll see how thick the tank straps are. As seen in the last photo, these were thinned using the Dremel tool and sanding disc. I did this so the tanks would not rub the track's guide rail.

Close-up of the truck fuel tanks and tank straps after their final sanding.

I used a piece of pine cut the same size as the frame to set the truck on to ensure everything cleared the bottom. Looking closely at the first image, you’ll see gaps above the rear fenders. I filled this gap using a thin piece of basswood. I placed the basswood next to the frame and the fender, and using a pencil, I traced around it. Next, I used scissors to cut these out carefully.

Big rig truck sitting on the schematics, with a thin piece of wood used as a shim held between the truck frame and the fenders.

I glued the pieces into place with CA glue (super glue). Once the glue cured, I sanded the fenders to shape. The last photo shows how the tanks will fit on the body. I glued them in place after painting, later in the build process.

Truck with the fender shim fitted in place and the fenders sanded to shape.

I sketched the grill bars and cut them out on the scroll saw. Window screen material and HVAC tape were used to make the bug screen attached to the grill. Both pieces were painted silver and later affixed to the truck.

Front grill of the cabin marked with pencil and cut on a scroll saw. Wire window screen material and HVAC tape used to form the bug screen for the front grill.

Next, I worked on a reversed T-bar panel for the tail lights. Using my miter box and X-acto razor saw, I cut 1/8" dowel rods to make tail lights. The tick marks on the light bar are where I will glue them on. After smearing glue on the piece of wood seen above the tweezers, I dipped each tail light into the glue and placed it onto the tail light bar. I glued the pieces on after painting.

Rear of big rig truck. Miter box used to cut dowel rod for use as rear taillight. Dowels on piece of wood to form rear light bar. Rear light bar glued in place on truck.

It’s important to perform test measurements as you go along. You can see that I am right at 8 1/2", as this is the max length the truck chassis can be for the class A 18-wheeler, according to the Mid-America and the West Coast Grand Prix Pinewood Derby Rules, which differ from BSA racing rules where the max length is 7 1/4" for the truck chassis and 17 1/2" overall length with trailer, and width of 3 3/4" and height of 4 1/2", according to the kit instructions. I have left the details on how I made the sleeping cabin out of this article as it is simply a pine box with a top.

Truck on schematic with tape measure stretched across front showing length of big rig.

Time to Start Painting!!

I started the process by painting several small parts silver using Testors model paint. While the small parts dried, I used craft paint to color the truck lime green and white. I taped off select areas so I could apply black paint.

Small truck parts painted silver. Parts of truck body painted white, green and black.

Next, I painted the lime green accent stripe by adding more tape above where I painted black and below where I wanted to leave it white.

Truck body sitting on wooden block partially painted with masking tape over certain areas.

Pictured below is a walk-around view of all the painted parts. Keep in mind that the cab top and the air horns were not glued down yet; this was just for viewing purposes.

Left side, front, and right side view of painted truck.

For the headlight bars, I used a 1/4" dowel rod, splitting it in half on the scroll saw. Next, I marked how wide to make it and where to place the headlights. Using my miter box and craft saw, I cut a 1/8" dowel rod to make the headlights. Next, I painted them with Testors model paints.

Wooden dowl rod cut in half on scroll saw and held to the truck to mark position for headlights. Dowel rods cut into pieces to form headlights. Headlights painted and glued in place on the front of the big rig.

Next, I made the windshield using 1/8" Plexiglass. In the second image, you can see how I held the Plexiglass to mark the needed size using a dry-erase marker. I cut the windshield out using a scroll saw with a crown-tooth blade, sanded it to fit using a disc sander, and then carefully glued it in place with CA glue.

Thin plastic used as windows and inserted in place on big rig truck.

For the door windows I used a sheet of thin plastic. Utilizing my pattern, I traced it with a Sharpie and cut it out using scissors. Next, I glued them to the inside of the cab with CA glue, then painted around the windshield using silver modeling paint.

Thin plastic used as for the side windows and inserted in place on big rig truck.

For the cab top details, you’ll see in the first image that I marked out placements for these parts. Next, I glued the air horns and used the tips of toothpicks to make the clearance lights. To do this, I marked on the toothpicks where to cut and then placed them on a block of wood one at a time and cut off the tips using an X-Acto knife. You don’t have to use a wood block, but I find this easier. I used tweezers to dip the toothpick tips in CA glue to attach the clearance lights and then placed them on top of the cab. After the glue dried, I painted them silver. After the silver dried, I put a touch of amber paint on them.

Air horns marked on top of truck and glued in place. Clearance lights painted silver and red, and glued in place.

I taped the pattern to a piece of pinewood using packing tape. As mentioned, this helps keep the pattern in place and acts as a lube for the scroll saw blade. I used a drill press and a 1/8" drill bit and made a hole for the trailer pin. The middle image shows it ready to cut on the scroll saw. The marks in the last photo indicate how I will shape it with a Dremel tool and a plate on the frame where I have marked the axle spacing in an X pattern to show where I will drill later.

Pattern from schematic for the trailer hitch on block of wood. Trailer hitch cut on scroll saw.

The first image below shows the frame plate for the fifth wheel hitch. Using a 1/8" drill bit and drill press, I made a hole at the center of the X to ensure the fifth wheel hitch was in the center of the frame. The following image shows how I glued the fifth wheel hitch by using the same drill bit, putting glue under the hitch, and sliding it down the drill bit to ensure everything was centered, as seen in the third image. The hitch was then painted black.

Plate for trailer hitch drilled on drill press, then glued to trailer hitch.

The materials I used to make the smokestacks were Woodmates Mr. Grip and K & S aluminum tubing, stock no.113 and no. 114. I marked where to cut with a sharpie using my pattern. I cut the no. 114 tubing with a Dremel and cutting disc and used a small file for cleaning up, removing any burrs. The last image below shows the longer no. 113 tubing. I shaped them using a disc sander.

Aluminum tubing for the smokestacks marked and cut with a Dremel, then shaped on a disc sander.

The first image below shows the burrs left behind from sanding the miter shape. The second photo shows them after deburring with a file. The third image below shows the smoke stacks with the smaller tube fitted in the larger tube. These are held in place with super glue. Also, in the same image, you’ll see the Mr. Grips out of the package. These were cut to size with scissors to make heat shields for the smokestacks.

Aluminum tubing for the smokestacks deburred with a flat file and inserted into each other, along with metal mesh to complete the smokestack design.

For the next step in constructing the smokestacks I placed the tubing over the Mr. Grip and rolled it to a C-shape. Next, I glued them in place and made sure I had a right-side and a left-side stack. The last image shows a good view of the bottom side of the truck and how I glued the stacks into place.

Metal mesh glued using Gorilla glue to aluminum tubing to complete the smokestack.

Cabin Details

The first image is a view down inside the cabin. As you can see, it is bare. At this point, you can choose not to add details and close it up. However, I like to add details. The second image shows how I drew the seat design on a piece of basswood. I used the same piece of basswood to make two seats by using a scroll saw to cut out the first one and then utilizing that as a template to draw out another seat.

View of inside of cabin from the top. Block of wood with seat design sketched on it. Chairs after cutting.

The first image shows the seats sitting inside the cab. They still need to be glued in, as they have yet to be painted. Next, I moved on to crafting a steering wheel using a paperclip and wrapping it around the dowel rod to make the circle portion of the steering wheel. I cut the remaining ends off using small modeling dikes to make it round. Using my soldering iron, a block of wood, and some painter's tape, I made the steering wheel's inner parts.

View of inside of cabin from the top. Wooden dowel used to form steering wheel from solder wire.

I made a loop in the tape and stuck it to the wood block to make a sticky pad for holding these parts. The first image below shows the circle part of the steering wheel. I then took a second paper clip, straightened it, and bent it to create the center of the steering wheel. I then cut the ends off the paperclip. In the second image, I took the rest of the paperclip, bent it in an L shape, and, using modeling hemostat forceps, held it in place and soldered the steering wheel in four areas, as seen in the last image.

Spokes of steering wheel formed with wire using forceps to hold wheel in place.

In the first image below, I used a small piece of scrap pine, a paperclip, and a seed bead to make the gear shift. The pine part was painted black and later assembled inside the cab, along with the steering wheel and painted seats, as seen in the next two photos.

Main gear shift. Top-down view of cabin with painted seats and steering wheel.

This next part might make you chuckle, as I "borrowed" a tongue depressor from my wife's speech-language pathology kit to use as a ruler/pattern for making the sleeper and cab door details. The second image below shows where I sanded the bottom of the stick to make it flatter and marked two lines from the pattern. These marks will be used later as a reference when I draw these details on the actual truck using a regular pencil. The photos below show the sleeper door detail close-up and far away.

Tongue depressor used to mark side of truck cabin for cabin door placement.

The first image is my hand-drawn mirror and CB antenna pattern. The second image shows the supplies I used to make them, which include seed beads, telephone cord wire, paperclips, a pop can, modeling pliers, and snips.

Sketch of CB antenna and supplies and tools used to make antenna.

Using my pattern above, I cut two lengths of telephone cord wire and stripped the ends. I then superglued two seed beads on. Later, after they dried, I snipped the copper ends off. Using my pattern, a Sharpie marked the paper clips, and pliers bent them to shape two mirror support brackets.

Telephone wire, beads, and wire marked for CB antenna.

Here’s an image of the CB antennas and mirror support brackets. Using a sharpie, I marked the CB antennas, which were later glued to the support brackets to ensure they were the same height as each other. Next, using a pop can and scissors, I cut both ends of the pop can off and used part of the inside to make the mirrors. The third image is a piece of aluminum from the inside of the pop can that was used to create two mirrors by cutting it to the height of my mirror pattern, using a random length marking a center line, and then cutting it in half. The aluminum was later folded in half around the mirror support brackets.

Wire for rearview mirror supports. Pop can cut to crate rearview mirrors. Review mirror marked at center.

I stuck these pieces using my tape sticky pad method and glued the antennas to the paper clip (mirror support brackets). This image shows the pop can mirrors folded in half and ready to glue once the mirror support brackets and antennas dry. Using my modeling hemostat forceps, I smeared CA glue to one side of the mirror and then clamped them with the forceps to dry.

Review mirror supports glue together. Mirror pieces folded in half and glued to mirror supports.

While the mirrors were drying, I moved on and used 1/8" chrome HVAC tape, a hobby knife, and a burnishing tool to make a chrome trim detail around the bottom of the cab and sleeper. In the first image below, I used my craft knife to remove the backing paper from the tape and then stick the tape to the blade while placing the tape on the truck. After placing the tape, I used the burnishing tool to rub it down.

Hobby knife, pencil, and HVAC tape used to make chrome detail around bottom of truck cabin.

Before installing the mirrors, I glued the top of the cab in place. I installed the mirrors using a Dremel, drill bits, a Sharpie, and modeling dikes.

Top-down view of truck cabin. View of completed rearview mirrors.

To install the mirrors, I held them to the truck and, using a Sharpie pen, made two little dots where I drilled these with the Dremel tool and a tiny drill bit. Then, I clipped the ends off the support brackets, put two dabs of CA glue where I drilled the holes, pushed the mirror support brackets into the holes, and let them dry. I repeated this process for the other side.

Side view of rearview mirrors glued to big rig cabin.

I sprayed one light coat using my paint stand and Rustoleum 2x Clear. The second picture is after the first coat. However, while the truck was drying, I noticed the cab would benefit from a sun visor. So, I drew out a pattern for the sun visor using what was left of the pop can and my cab top pattern.

Can of clear coat paint and paint stand. Truck on paint stand after clear coating. Template of sun visor used to place marks on pop can.

I cut the visor out with scissors and then used sandpaper to remove the black Sharpie ink. Next, I used the edge of the block of wood to help bend and shape the visor. The second photo shows the visor smeared with glue and ready to be stuck to the cab. The third image shows the front view of the sun visor. Lastly, I sprayed the cab with two more coats of clear spray paint.

Pop can cut to from sun visor. Sun visor glued in place to the cabin. Top-down front view of cabin.

Axle and Wheel Preparation

Using my new lathe, which my wife and son bought me for my birthday, I turned out 22 wheels. Next, as seen in the third picture, I prepped the wheels using Turbo Chucks and the Turbo Wheel Prep Kit. Shew! That was a lot of wheels!

Pinewood Derby wheels on lathe being cut to size and polished using Turbo Chucks and Turbo Derby wheel polish.

Next, I moved on to polishing the axles using Turbo Derby's Axle Prep Kit (top center photo). The left image shows the lighted magnification I use in front of my drill press. The images below center and to the right were taken with my cell phone held up to the magnifier. There are 12 axles in all: two 1" short axles and ten 1 3/8" long axles.

A drill press and magnifying light used to polish axles. Turbo Derby axle polishing kit. Polished axles and axle in a drill press.

Completing the Cabin

Because I thought the truck looked too boring with just plain black wheels, I used a silver Sharpie to color in the spokes and rim of each wheel, except for the inside duals. Below are left and ride-side views of the completed cabin.

Pinewood Derby wheel and silver Sharpie marker. Close-up of wheel with spokes colored silver. Side view of big rig with completed wheels.

Building the Trailer

I stack-cut two pieces using 1/8" Baltic birch plywood, making a right and left side for the trailer. You may note in my pattern that I had to change where it would attach to the truck due to my homemade 5th-wheel hitch. The picture below shows how much I had to raise it.

Schematic for truck trailer sitting on Baltic birch plywood. The wood cut in scroll saw.

The first image shows how I glued the floor into the bottom of the trailer by using spacers to hold everything square. In the second photo, you can see the bottom side of the trailer. I glued a 1/4" piece of pinewood to the nose, as I thought it would make it stronger for mounting the hitch pin. The third image is a view of the front of the trailer, so you can see how I made it step up so it can hitch to the truck.

Wood parts of trailer glued and clamped together.

The first image shows the bottom view of the trailer with 1 3/4" wide marks to help center the trailer chassis. I used a Turbo Jig Hybrid XL to drill the axle holes in the chassis. In the third image, you can see the chassis where I glued a 1/8" spacer. This needed to be done so the wheels would clear the bottom of the trailer floor.

Trailer chassis drilled using Turbo Jig XL Hybrid. Plywood spacer glued to truck chassis.

As seen below, I installed all the wheels and axles and glued the chassis to the trailer box. In the following image, I test-fitted the trailer to the truck. The photo below shows that I glued support blocks to help hold the trailer top down while gluing. They are spaced 1/8" down so that everything fits flush when I glue the 1/8" top down.

Trailer pieces clamped and glued in place.

The first image below shows the top glued and clamped down. The second image shows the finished top. Photo three is a view of the back of the trailer. I made a fold-down rear door using toothpicks as hinge pins. I painted the underside black, keeping a spot unpainted so I could place my name and date.

More trailer pieces clamped and glued in place. Bottom of trailer painted black.

In the first image below, the trailer box has been painted white. I thought the trailer looked boring all white, so I came up with this paint scheme using markers on a piece of paper. This third image shows the paint scheme image etched out on the trailer. I used thin orange painter's tape to mask off the green accent stripes.

Side of trailer with paint pattern sketched on it.

The first image shows the black detail added to the trailer. I then put the trailer on the truck to ensure the paint lines flowed from the cab to the trailer and realized the black needed to be higher. Next, you can see how I raised the black and painted the top lime green. Then, I sprayed it lightly with one coat of clear paint. I made small safety reflectors for the trailer using reflective safety tape and a parallel cutter.

Trailer pattern painted with white, black, and green paint.

The first image below is the tape I used to make the clearance lights. The second photo shows the tools I used to apply the stickers to the trailer. The third image is the hitch pin I made for the trailer out of 1/8" cold roll steel. The truck is now complete!!